At this point not too much but 5 usually means its staple in my closet. I have/will buy backups of it. This represents about 25% of my collection.
4 stars represent 75% of my collections. Items I love and happy that will last me many years because of the huge collection I have. So there is no need for a backup.
I don't own anything I rate less than 4 stars because between the 150 perfumes of 4 and 5 stars in my collection, I don't have time for anything less.